docs: def scale(self, quantity):
          """Scales the given process to the given number of dynos."""
  
          r = self._h._http_resource(
              method='POST',
              resource=('apps', self.app.name, 'ps', 'scale'),
              data={'type': self.type, 'qty': quantity}
          )
  
          r.raise_for_status()
  
          try:
              return self.app.processes[self.type]
          except KeyError:
              return ProcessListResource()